August 24, 2005
Wednesday

Igor Dmitrenko looks in wonder at satellite images of ice on top of the world these days. After more than a decade of trips to the Arctic Ocean north of Russia, he's noticed open water where icebreakers had to bash through in recent years.

"This year's ice situation is absolutely unique," said Dmitrenko, an oceanographer and visiting associate professor at the International Arctic Research Center at the University of Alaska Fairbanks. "The Laptev Sea is already open to 81 degrees north. I've never seen that in my life. Usually it's closed to 75 degrees."

The lack of ice covering the southern Laptev Sea, above central Siberia on the map, means that Dmitrenko and 68 others might have easy passage on an icebreaker during a September 2005 voyage. During the trip, a "summer school" organized by the International Arctic Research Center, a group of scientists and students will learn more about a pulse of warm Atlantic water that has invaded the Arctic Ocean and may be eating at the sea ice from below.

According to the National Snow and Ice Data Center in Boulder, Colorado, sea ice floating on the Arctic Ocean has decreased in a steady fashion since dependable measurements started in 1978.

What's causing the sea ice to melt? Many scientists point to warmer air temperatures in the Arctic, but the pulse of warm Atlantic water Dmitrenko and his coworkers discovered might also be a factor. On a similar Arctic Ocean voyage on a Russian icebreaker in 2004, Dmitrenko gathered information from scientific instruments moored in place in the ocean. Each day, the instruments record vertical profiles of ocean water temperature, as well as salinity and ocean currents.

One of those instruments north of the Laptev Sea recorded a jump in water temperature on a February 2004 day as a column of warm water flooded past the instrument, which was between 492 to 1,968 feet (150 and 600 meters) below the ocean surface. That temperature increase, from about 32.7 to 33.4 degrees Fahrenheit (.4 to .8 degree Celsius) is a big change in the stable environment of the Arctic Ocean.

Dmitrenko and his colleagues contacted oceanographers in Russia, Norway and Germany to help backtrack the warmer water, and they found it passed Norway in 1998 and took six years to reach the continental slope of the Laptev Sea. That warmer water now resides in the Arctic Ocean, where it will remain for years caught up in currents that swirl counterclockwise in giant undersea basins.

During this year's summer school, students from Russia, Canada, America, Belgium, France, Sweden, Denmark and Norway will join researchers and instructors on a 22-day trip aboard an icebreaker on the Laptev Sea portion of the Arctic Ocean. The expedition will depart from Kirkenes, Norway, on September 6. During the trip at sea, college students will work on research projects and help researchers like Dmitrenko retrieve information from moorings that are measuring the ocean's characteristics. Dmitrenko will also install three new moorings to gather more information about the pulse of warm Atlantic water that's entered the Arctic.

As his voyage grows closer, Dmitrenko checks the World Wide Web each day for ice conditions on the Laptev Sea. He thinks the icebreaker, capable of plowing through sea ice six-feet-thick, may have an easier time this year.
"Last year was very hard in terms of ice conditions," he said. "Maybe we can skirt more of the ice this year."

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